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Operational amplifiers play a vital role in modern electronics design. The latest op amps have powerful new features, making them more suitable for use in many products requiring weak signal amplification, such as medical devices, communications technology, optical networks, and sensor interfacing. The Op Amp Applications Handbook may well be the ultimate op amp reference book available. This book is brimming with up-to-date application circuits, valuable design tips, and in-depth coverage of the latest techniques to simplify op amp circuit designs, and improve their performance. As an

Operational amplifiers --- Amplifiers (Electronics) --- Amps (Electronics) --- Electronic amplifiers --- Radio amplifiers --- Electronics

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Different kinds of electronic load simulators for testing of power supply have been developed and commercialised. A programmable RLC impedance with adjustable R, L and C can be useful to simulate the load of a generator like a motor for example. Some companies may be interested in testing their voltage/current generators under some conditions and study their behaviours. Both inductive and capacitive loads can be simulated by adjusting the phase difference between the voltage and current waveforms.

However, there exist many drawbacks, for example, it can provide only 4 modes including constant resistance (pure resistive load), constant power, constant current and constant voltage to simulate simple dc load. But more often, they cannot simulate a RL or RC load with a good dynamic response. The main objective of this master thesis is to design, manufacture and test a programmable RLC impedance. This circuit must cover the entire inductive-resistive-capacitive range (voltage/current phase shift between -90° and
+90°). The RLC load must be able to dissipate up to 5 W. Two different implementations are suggested: the analog and digital RLC impedance with their pros and cons. The first step is to design an analog impedance. A gyrator is used in order to simulate an non ideal inductor with parallel redundant resistor. The main property of the gyrator is to invert the current-voltage characteristic of an electrical component. This way, a capacitor can be used to get a non-ideal variable inductor. The inductance can be adjusted with simple potentiometers. The second step consists in removing the parallel resistors in order to simulate an ideal inductor and reach the 90° phase-shift. This objective can be achieved by connecting the Negative Impedance Converter (N.I.C) in
parallel to the gyrator. After that, a more detailed study of the output current and
output voltage across the op amps allows to highlight the main limitations of such
circuits. The voltage and current saturation of the op amps limit the available range of inductance/capacitance values. Several simulations with a real precision op amp (AD744) are performed. Finally, those circuits have been implemented on a breadboard in the CSL laboratory1 with commercial op amps such as the famous LM324. The results in terms of output current are compared with the simulations.
The second step consists in designing a digital RLC impedance. By contrast to the analog impedance, the filtering process is done digitally using the microcontroller ATMEGA2560. A software feedback control approach is employed to adjust the current amplitude and the power factor. The objective is to maintain the impedance value constant regardless of the variation of the source voltage amplitude. Many parameters such as the sampling frequency and the resolution of the ADC/DAC may affect the quality of the output current. The voltage is converted to current using a Howland current source. Several simulations have been performed to visualise the performance of the digital RLC filter.

Finally, the analog and digital programmable RLC impedances are compared in terms of their maximum input voltage, inductance/capacitance range, frequency, ... It will be shown that the digital implementation offers more flexibility to the range of the inductance/capacitance values than the analog impedance.

impedance, filter, op amps, analog, digital --- programmable --- Ingénierie, informatique & technologie > Ingénierie électrique & électronique

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OP Amps deliberately straddles that imaginary line between the technician and engineering worlds. Topics are carefully addressed on three levels: operational overview, numerical analysis, and design procedures. Troubleshooting techniques are presented that rely on the application of fundamental electronics principles. Systematic methods are shown that can be used to diagnose defects in many kinds of circuits that employ operational amplifiers.One of the book's greatest strengths is the easy-to-read conversational writing style. The author speaks directly to the student in a manner

Operational amplifiers. --- Operational amplifiers --- Electrical & Computer Engineering --- Engineering & Applied Sciences --- Electrical Engineering --- Amplifiers (Electronics) --- Amps (Electronics) --- Electronic amplifiers --- Radio amplifiers --- Electronics

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Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling the

Audio amplifiers. --- Amplifiers (Electronics) --- Amps (Electronics) --- Electronic amplifiers --- Radio amplifiers --- Electronics --- Amplifiers, Audio --- Audio-frequency amplifiers --- Audio amplifiers --- Design and construction. --- Maintenance and repair.

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Electronic apparatus and appliances. --- Amplifiers (Electronics) --- Electronic devices --- Electronics --- Physical instruments --- Scientific apparatus and instruments --- Electronic instruments --- Amps (Electronics) --- Electronic amplifiers --- Radio amplifiers --- Apparatus and appliances --- MATLAB. --- MATLAB (Computer program) --- MATLAB (Computer file) --- Matrix laboratory